1. Field of the Invention
The present invention relates to a drive unit and a drive module.
2. Description of the Related Art
Japanese Patent Application Publication No. 9-322311 (JP 9-322311 A), for example, describes a vehicle control device according to the related art that is provided in a vehicle to control rotation of a motor that generates a drive force on a drive shaft that transmits torque to drive wheels. In the vehicle control device, motors such as a clutch motor and an assist motor are controlled to control torque to be transferred to the drive wheels.
In a vehicle control device such as that according to JP 9-322311 A, a target value is derived so that torque that corresponds to the amount by which a driver depresses an accelerator pedal is output as described in relation to control during rearward travel of a vehicle. A torque command value is set in accordance with the derived target value so as to cause the clutch motor and the assist motor to output torque.
In some cases, torque transferred from each motor to the drive wheels passes through a drive unit that includes a speed reducer. The drive unit includes a plurality of gears rotatably supported by a plurality of bearings, and a load acts on the bearings because of rotation of the gears when the vehicle travels forward or rearward.
If the vehicle control device according to JP 9-322311 A is applied to the drive unit, the difference between the magnitude of a load that acts on the bearings during forward travel of the vehicle and the magnitude of such a load during rearward travel of the vehicle is not taken into consideration in deriving the target value. Thus, bearings that can support the maximum load are selected irrespective of whether the vehicle is traveling forward or rearward. Therefore, large bearings are selected irrespective of the load that actually acts on the bearings, which is disadvantageous in terms of reducing the size of the drive unit.